I just used the spring mass formula. Fn= 1/2Pi * (k/M)^0.5
So my 165 lbs speakers needed 4, 57 lbs/in springs for a 3.3 Hz resonance. That particular spring was available on the McMaster Carr website.
So my 165 lbs speakers needed 4, 57 lbs/in springs for a 3.3 Hz resonance. That particular spring was available on the McMaster Carr website.